Source lights are used in a variety of applications, such as providing general illumination and providing light for electronic displays (e.g., LCDs). Historically, incandescent source lights have been widely used for general illumination purposes. Incandescent source lights produce light by heating a filament wire to a high temperature until it glows. The hot filament is protected from oxidation in the air with a glass enclosure that is filled with inert gas or evacuated. Incandescent source lights are gradually being replaced in many applications by other types of electric lights, such as fluorescent lamps, compact fluorescent lamps (CFL), cold cathode fluorescent lamps (CCFL), high-intensity discharge lamps, and solid state source lights, such as light-emitting diodes (LEDs).